Spring Data JPA:Spring Data JPA 是spring data 項目下的一個模塊。提供了一套基於JPA標準操作數據庫的簡化方案。底層默認的是依賴 Hibernate JPA 來實現的。Spring Data JPA 的技術特點:我們只需要定義接口並集成 Spring Data JPA 中所提供的接口就可以了。不需要編寫接口實現類。
一:創建 Spring Data JPA項目
1:導入jar包
https://download.csdn.net/download/qq_36297434/11890694
2:配置文件
2.1:jdbc.properties
jdbc.url=jdbc:mysql://localhost:3306/test
jdbc.driver.class=com.mysql.jdbc.Driver
jdbc.username=root
jdbc.password=root
2.2:applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:jpa="http://www.springframework.org/schema/data/jpa"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/data/jpa
http://www.springframework.org/schema/data/jpa/spring-jpa.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd">
<!-- 配置讀取properties文件的工具類 -->
<context:property-placeholder location="classpath:jdbc.properties"/>
<!-- 配置c3p0數據庫連接池 -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="jdbcUrl" value="${jdbc.url}"/>
<property name="driverClass" value="${jdbc.driver.class}"/>
<property name="user" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
</bean>
<!-- Spring整合JPA 配置EntityManagerFactory-->
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<!-- hibernate相關的屬性的注入 -->
<!-- 配置數據庫類型 -->
<property name="database" value="MYSQL"/>
<!-- 正向工程 自動創建表 -->
<property name="generateDdl" value="true"/>
<!-- 顯示執行的SQL -->
<property name="showSql" value="true"/>
</bean>
</property>
<!-- 掃描實體的包 -->
<property name="packagesToScan">
<list>
<value>hhxy.pojo</value>
</list>
</property>
</bean>
<!-- 配置Hibernate的事務管理器 -->
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>
<!-- 配置開啓註解事務處理 -->
<tx:annotation-driven transaction-manager="transactionManager"/>
<!-- 配置springIOC的註解掃描 -->
<context:component-scan base-package="hhxy"/>
<!-- Spring Data JPA 的配置 -->
<!-- base-package:掃描dao接口所在的包 -->
<jpa:repositories base-package="hhxy.dao"/>
</beans>
3:編寫Dao
public interface UsersDao extends JpaRepository<Users, Integer> {
}
4:編寫測試代碼
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class UsersDaoImplTest {
@Autowired
private UsersDao usersDao;
/**
* 添加用戶
*/
@Test
@Transactional// 在測試類對於事務提交方式默認的是回滾。
@Rollback(false)//取消自動回滾
public void testInsertUsers(){
Users users = new Users();
users.setUserage(24);
users.setUsername("張三");
this.usersDao.save(users);
}
}
二:Spring Data JPA的繼承結構
三、 Spring Data JPA的運行原理
@PersistenceContext(name="entityManagerFactory")
private EntityManager em;
@Test
public void test1(){
//org.springframework.data.jpa.repository.support.SimpleJpaRepository@fba8bf
//System.out.println(this.usersDao);
//class com.sun.proxy.$Proxy29 代理對象 是基於 JDK 的動態代理方式創建的
//System.out.println(this.usersDao.getClass());
JpaRepositoryFactory factory = new JpaRepositoryFactory(em);
//getRepository(UsersDao.class);可以幫助我們爲接口生成實現類。而這個實現類是 SimpleJpaRepository 的對象
//要求:該接口必須要是繼承 Repository 接口
UsersDao ud = factory.getRepository(UsersDao.class);
System.out.println(ud);
System.out.println(ud.getClass());
}
四:Repository接口
Repository 接口是 Spring Data JPA 中爲我我們提供的所有接口中的頂層接口Repository 提供了兩種查詢方式的支持:基於方法名稱命名規則查詢,基於@Query 註解查詢。
1:方法名稱命名規則查詢
規則:findBy(關鍵字)+屬性名稱(屬性名稱的首字母大寫)+查詢條件(首字母大寫)
關鍵字 | 方法命名 | sql where 字句 |
And | findByNameAndPwd | where name= ? and pwd =? |
Or | findByNameOrSex | where name= ? or sex=? |
Is,Equal | findById,findByIdEquals | where id= ? |
Between | findByIdBetween | where id between ? and ? |
LessThan | findByIdLessThan | where id < ? |
LessThanEqual | findByIdLessThanEqual | where id <= ? |
GreaterThan | findByIdGreaterThan | where id > ? |
GreaterThanEqual | findByIdGreaterThanEquals | where id > = ? |
After | findByIdAfter | where id > ? |
Before | findByIdBefore | where id < ? |
IsNull | findByNameIsNull | where name is null |
isNotNull,Not Null | findByNameNotNull | where name is not Null |
Like | findByNameLike | where name like ? |
NotLike | findByNameNotLike | where name not like ? |
StartingWith | findByNameStartingWith | where name like '?%' |
EndingWith | findByNameEndingWith | where name like '%?' |
Containing | findByNameContaining | where name like '%?%' |
OrderBy | findByIdOrderByXDesc | where id=? order by x desc |
Not | findByNameNot | where name <> ? |
In | findByIdIn(Collection <?> c) | where id in (?) |
NotIn | findByIdNotIn(Collection<?> c) | where id not in (?) |
True | findByAaaTue | where aaa = true |
False | findByAaaFalse | where aaa = false |
IgnoreCase | findByNameIgnoreCase | where UPPER(name)=UPPER(?) |
1.1:創建接口
/**
* Repository 接口講解
* @author 李偉康
*
*/
public interface UsersDao extends Repository<Users, Integer> {
List<Users> findByUsernameIs(String string);
List<Users> findByUsernameLike(String string);
List<Users> findByUsernameAndUserageGreaterThanEqual(String name,Integer age);
}
1.2:測試類
/**
* Repository 接口測試
* @author 李偉康
*
*/
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class RepositoryTest {
@Autowired
private UsersDao usersDao;
/**
* 需求:使用用戶名作爲查詢條件
*/
@Test
public void test1(){
/**
* 判斷相等的條件,有三種表示方式
* 1,什麼都不寫,默認的就是做相等判斷
* 2,Is
* 3,Equal
*/
List<Users> list = this.usersDao.findByUsernameIs("王五");
for (Users users : list) {
System.out.println(users);
}
}
/**
* 需求:根據用戶姓名做 Like 處理
* Like:條件關鍵字
*/
@Test
public void test2(){
List<Users> list = this.usersDao.findByUsernameLike("王%");
for (Users users : list) {
System.out.println(users);
}
}
/**
* 需求:查詢名稱爲王五,並且他的年齡大於等於 22 歲
*/
@Test
public void test3(){
List<Users> list = this.usersDao.findByUsernameAndUserageGreaterThanEqual("王五", 22);
for (Users users : list) {
System.out.println(users);
}
}
}
2:基於@Query註解的查詢
2.1:通過JPQL語句查詢
JPQL:通過 Hibernate 的 HQL 演變過來的。他和 HQL 語法及其相似。
2.1.1:創建接口
/**
* Repository 接口講解
* @author 李偉康
*
*/
public interface UsersDao extends Repository<Users, Integer> {
//方法名稱命名規則
List<Users> findByUsernameIs(String string);
List<Users> findByUsernameLike(String string);
List<Users> findByUsernameAndUserageGreaterThanEqual(String name,Integer age);
//使用@Query 註解查詢
@Query(value="from Users where username = ?")
List<Users> queryUserByNameUseJPQL(String name);
@Query("from Users where username like ?")
List<Users> queryUserByLikeNameUseJPQL(String name);
@Query("from Users where username = ? and userage >= ?")
List<Users> queryUserByNameAndAge(String name,Integer age);
}
2.1.2:測試類
/**
* 測試@Query 查詢 JPQL
*/
@Test
public void test4(){
List<Users> list = this.usersDao.queryUserByNameUseJPQL("王五");
for (Users users : list) {
System.out.println(users);
}
}
/**
* 測試@Query 查詢 JPQL
*/
@Test
public void test5(){
List<Users> list = this.usersDao.queryUserByLikeNameUseJPQL("王%");
for (Users users : list) {
System.out.println(users);
}
}
/**
* 測試@Query 查詢 JPQL
*/
@Test
public void test6(){
List<Users> list = this.usersDao.queryUserByNameAndAge("王五",22);
for (Users users : list) {
System.out.println(users);
}
}
2.2:通過SQL語句查詢
2.2.1:創建接口
/**
* Repository 接口講解
* @author 李偉康
*
*/
public interface UsersDao extends Repository<Users, Integer> {
//方法名稱命名規則
List<Users> findByUsernameIs(String string);
List<Users> findByUsernameLike(String string);
List<Users> findByUsernameAndUserageGreaterThanEqual(String name,Integer age);
//使用@Query 註解查詢
@Query(value="from Users where username = ?")
List<Users> queryUserByNameUseJPQL(String name);
@Query("from Users where username like ?")
List<Users> queryUserByLikeNameUseJPQL(String name);
@Query("from Users where username = ? and userage >= ?")
List<Users> queryUserByNameAndAge(String name,Integer age);
//使用@Query 註解查詢 SQL
//nativeQuery:默認的是 false.表示不開啓 sql 查詢。是否對 value 中的語句做轉義。
@Query(value="select * from t_users where username = ?",nativeQuery=true)
List<Users> queryUserByNameUseSQL(String name);
@Query(value="select * from t_users where username like ?",nativeQuery=true)
List<Users> queryUserByLikeNameUseSQL(String name);
@Query(value="select * from t_users where username = ? and userage >= ?",nativeQuery=true)
List<Users> queryUserByNameAndAgeUseSQL(String name,Integer age);
}
2.2.2:測試類
/**
* 測試@Query 查詢 SQL
*/
@Test
public void test7(){
List<Users> list = this.usersDao.queryUserByNameUseSQL("王五");
for (Users users : list) {
System.out.println(users);
}
}
/**
* 測試@Query 查詢 SQL
*/
@Test
public void test8(){
List<Users> list = this.usersDao.queryUserByLikeNameUseSQL("王%");
for (Users users : list) {
System.out.println(users);
}
}
/**
* 測試@Query 查詢 SQL
*/
@Test
public void test9(){
List<Users> list = this.usersDao.queryUserByNameAndAgeUseSQL("王五", 22);
for (Users users : list) {
System.out.println(users);
}
}
3:通過@Query註解完成數據更新
3.1:創建接口
@Query("update Users set userage = ? where userid = ?")
@Modifying //@Modifying 當前語句是一個更新語句
void updateUserAgeById(Integer age,Integer id);
3.2:測試類
/**
* 測試@Query update
*/
@Test
@Transactional
@Rollback(false)
public void test10(){
this.usersDao.updateUserAgeById(24, 5);
}
五:CrudRepository接口
1:創建接口
/**
* CrudRepository 接口講解
* @author 李偉康
*
*/
public interface UsersDao extends CrudRepository<Users, Integer> {
}
2:測試代碼
/**
* CrudRepository 接口測試
* @author 李偉康
*
*/
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class RepositoryTest {
@Autowired
private UsersDao usersDao;
/**
* 添加單條數據
*/
@Test
public void test1(){
Users user = new Users();
user.setUserage(21);
user.setUsername("趙小麗");
this.usersDao.save(user);
}
/**
* 批量添加數據
*/
@Test
public void test2(){
Users user = new Users();
user.setUserage(21);
user.setUsername("趙小麗");
Users user1 = new Users();
user1.setUserage(25);
user1.setUsername("王小虎");
List<Users> list= new ArrayList<>();
list.add(user);
list.add(user1);
this.usersDao.save(list);
}
/**
* 根據 ID 查詢單條數據
*/
@Test
public void test3(){
Users users = this.usersDao.findOne(13);
System.out.println(users);
}
/**
* 查詢全部數據
*/
@Test
public void test4(){
List<Users> list = (List<Users>)this.usersDao.findAll();
for (Users users : list) {
System.out.println(users);
}
}
/**
* 刪除數據
*/
@Test
public void test5(){
this.usersDao.delete(13);
}
/**
* 更新數據 方式一
*/
@Test
public void test6(){
Users user = this.usersDao.findOne(12);
user.setUsername("王小紅");
this.usersDao.save(user);
}
/**
* 更新數據 方式二
*/
@Test
@Transactional
@Rollback(false)
public void test7(){
Users user = this.usersDao.findOne(12);//持久化狀態的
user.setUsername("王小小");
}
}
六:PagingAndSortingRepository接口
1:分頁處理
1.1:創建接口
/**
* PagingAndSortingRepository 接口講解
* @author Administrator
*
*/
public interface UsersDao extends PagingAndSortingRepository<Users,Integer>{
}
1.2:測試代碼
/**
* CrudRepository 接口測試
* @author 李偉康
*
*/
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class RepositoryTest {
@Autowired
private UsersDao usersDao;
/**
* 分頁
*/
@Test
public void test1(){
int page = 2; //page:當前頁的索引。注意索引都是從 0 開始的。
int size = 3;// size:每頁顯示 3 條數據
Pageable pageable= new PageRequest(page, size);
Page<Users> p = this.usersDao.findAll(pageable);
System.out.println("數據的總條數:"+p.getTotalElements());
System.out.println("總頁數:"+p.getTotalPages());
List<Users> list = p.getContent();
for (Users users : list) {
System.out.println(users);
}
}
}
2:排序的處理
2.1:測試代碼
/**
* 對單列做排序處理
*/
@Test
public void test2(){
//Sort:該對象封裝了排序規則以及指定的排序字段(對象的屬性來表示)
//direction:排序規則
//properties:指定做排序的屬性
Sort sort = new Sort(Direction.DESC,"userid");
List<Users> list = (List<Users>)this.usersDao.findAll(sort);
for (Users users : list) {
System.out.println(users);
}
}
/**
* 多列的排序處理
*/
@Test
public void test3(){
//Sort:該對象封裝了排序規則以及指定的排序字段(對象的屬性來表示)
//direction:排序規則
//properties:指定做排序的屬性
Order order1 = new Order(Direction.DESC,"userage");
Order order2 = new Order(Direction.ASC,"username");
Sort sort = new Sort(order1,order2);
List<Users> list = (List<Users>)this.usersDao.findAll(sort);
for (Users users : list) {
System.out.println(users);
}
}
七:JpaRepository接口
JpaRepository 接口是我們開發時使用的最多的接口。其特點是可以幫助我們將其他接口的方法的返回值做適配處理。可以使得我們在開發時更方便的使用這些方法。
1:創建接口
/**
* JpaRepository 接口講解
* @author Administrator
*
*/
public interface UsersDao extends JpaRepository<Users, Integer>{
}
2:測試代碼
/**
* JpaRepository 接口測試
* @author 李偉康
*
*/
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class RepositoryTest {
@Autowired
private UsersDao usersDao;
/**
* 查詢全部數據
*/
@Test
public void test1(){
List<Users> list = this.usersDao.findAll();
for (Users users : list) {
System.out.println(users);
}
}
}
八:JpaSpecificationExecutor接口
完成多條件查詢,並且支持分頁與排序
1:單條件查詢
1.1:創建接口
/**
* JpaSpecificationExecutor 接口講解
* @author 李偉康
*注意:JpaSpecificationExecutor<Users>:不能單獨使用,需要配合着jpa中的其他接口一起使用
*/
public interface UsersDao extends JpaRepository<Users,Integer>,JpaSpecificationExecutor<Users>{
}
1.2:測試代碼
/**
* JpaRepository 接口測試
* @author Administrator
*
*/
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class RepositoryTest {
@Autowired
private UsersDao usersDao;
/**
* 需求:根據用戶姓名查詢數據
*/
@Test
public void test1(){
Specification<Users> spec = new Specification<Users>() {
/**
* @return Predicate:定義了查詢條件
* @param Root<Users> root:根對象。封裝了查詢條件的對象
* @param CriteriaQuery<?> query:定義了一個基本的查詢.一般不使用
* @param CriteriaBuilder cb:創建一個查詢條件
*/
@Override
public Predicate toPredicate(Root<Users> root,CriteriaQuery<?> query, CriteriaBuilder cb) {
Predicate pre = cb.equal(root.get("username"), "王五");
return pre;
}
};
List<Users> list = this.usersDao.findAll(spec);
for (Users users : list) {
System.out.println(users);
}
}
}
2:多條件查詢
2.1:給定查詢條件方式一
/**
* 多條件查詢 方式一
* 需求:使用用戶姓名以及年齡查詢數據
*/
@Test
public void test2(){
Specification<Users> spec = new Specification<Users>() {
@Override
public Predicate toPredicate(Root<Users> root,CriteriaQuery<?> query, CriteriaBuilder cb) {
List<Predicate> list = new ArrayList<>();
list.add(cb.equal(root.get("username"),"王五"));
list.add(cb.equal(root.get("userage"),24));
//此時條件之間是沒有任何關係的。
Predicate[] arr = new Predicate[list.size()];
return cb.and(list.toArray(arr));
}
};
List<Users> list = this.usersDao.findAll(spec);
for (Users users : list) {
System.out.println(users);
}
}
2.2:給定查詢條件方式二
/**
* 多條件查詢 方式二
* 需求:使用用戶姓名或者年齡查詢數據
*/
@Test
public void test3(){
Specification<Users> spec = new Specification<Users>() {
@Override
public Predicate toPredicate(Root<Users> root,CriteriaQuery<?> query, CriteriaBuilder cb) {
return cb.or(cb.equal(root.get("username"),"王五"),cb.equal(root.get("userage"), 25));
}
};
List<Users> list = this.usersDao.findAll(spec);
for (Users users : list) {
System.out.println(users);
}
}
3:分頁
/**
* 需求:查詢王姓用戶,並且做分頁處理
*/
@Test
public void test4(){
//條件
Specification<Users> spec = new Specification<Users>() {
@Override
public Predicate toPredicate(Root<Users> root,CriteriaQuery<?> query, CriteriaBuilder cb) {
return cb.like(root.get("username").as(String.class),"王%");
}
};
//分頁
Pageable pageable = new PageRequest(2, 2);
Page<Users> page = this.usersDao.findAll(spec, pageable);
System.out.println("總條數:"+page.getTotalElements());
System.out.println("總頁數:"+page.getTotalPages());
List<Users> list = page.getContent();
for (Users users : list) {
System.out.println(users);
}
}
4:排序
/**
* 需求:查詢數據庫中王姓的用戶,並且根據用戶 id 做倒序排序
*/
@Test
public void test5(){
//條件
Specification<Users> spec = new Specification<Users>() {
@Override
public Predicate toPredicate(Root<Users> root,CriteriaQuery<?> query, CriteriaBuilder cb) {
return cb.like(root.get("username").as(String.class),"王%");
}
};
//排序
Sort sort = new Sort(Direction.DESC,"userid");
List<Users> list = this.usersDao.findAll(spec, sort);
for (Users users : list) {
System.out.println(users);
}
}
5:分頁與排序
/**
* 需求:查詢數據庫中王姓的用戶,做分頁處理,並且根據用戶 id 做倒序排序
*/
@Test
public void test6(){
//排序等定義
Sort sort = new Sort(Direction.DESC,"userid");
//分頁的定義
Pageable pageable = new PageRequest(2,2, sort);
//查詢條件
Specification<Users> spec = new Specification<Users>() {
@Override
public Predicate toPredicate(Root<Users> root,
CriteriaQuery<?> query, CriteriaBuilder cb) {
return cb.like(root.get("username").as(String.class),"王%");
}
};
Page<Users> page = this.usersDao.findAll(spec, pageable);
System.out.println("總條數:"+page.getTotalElements());
System.out.println("總頁數:"+page.getTotalPages());
List<Users> list = page.getContent();
for (Users users : list) {
System.out.println(users);
}
}
九:用戶自定義Repository
1:創建接口
public interface UsersRepository {
public Users findUserById(Integer userid);
}
2:使用接口
/**
* 用戶自定義 Repository 接口講解
* @author 李偉康
*/
public interface UsersDao extends JpaRepository<Users,Integer>,JpaSpecificationExecutor<Users>,UsersRepository{
}
3:創建接口實現類
public class UsersDaoImpl implements UsersRepository {
@PersistenceContext(name="entityManagerFactory")
private EntityManager em;
@Override
public Users findUserById(Integer userid) {
System.out.println("MyRepository......");
return this.em.find(Users.class, userid);
}
}
4:編寫測試代碼
/**
* JpaRepository 接口測試
* @author 李偉康
*
*/
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class RepositoryTest {
@Autowired
private UsersDao usersDao;
/**
* 需求:根據用戶 ID 查詢數據
*/
@Test
public void test1(){
Users users = this.usersDao.findUserById(5);
System.out.println(users);
}
}
十:關聯映射操作
1: 一對一的關聯關係
需求:用戶與角色的一對一的關聯關係
用戶:一方
角色:一方
1.1:創建Users實體
@Entity
@Table(name="t_users")
public class Users implements Serializable{
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)//strategy=GenerationType.IDENTITY 自增長
@Column(name="userid")
private Integer userid;
@Column(name="username")
private String username;
@Column(name="userage")
private Integer userage;
public Roles getRoles() {
return roles;
}
public void setRoles(Roles roles) {
this.roles = roles;
}
@OneToOne
//@JoinColumn:就是維護一個外鍵
@JoinColumn(name="roles_id")
private Roles roles;
public Integer getUserid() {
return userid;
}
public void setUserid(Integer userid) {
this.userid = userid;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public Integer getUserage() {
return userage;
}
public void setUserage(Integer userage) {
this.userage = userage;
}
@Override
public String toString() {
return "Users [userid=" + userid + ", username=" + username + ",userage=" + userage + "]";
}
}
1.2:創建Roles實體
@Entity
@Table(name="t_roles")
public class Roles {
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="roleid")
private Integer roleid;
@Column(name="rolename")
private String rolename;
@OneToOne(mappedBy="roles")
private Users users;
public Users getUsers() {
return users;
}
public void setUsers(Users users) {
this.users = users;
}
public Integer getRoleid() {
return roleid;
}
public void setRoleid(Integer roleid) {
this.roleid = roleid;
}
public String getRolename() {
return rolename;
}
public void setRolename(String rolename) {
this.rolename = rolename;
}
}
1.3:一對一關聯關係操作
/**
* 一對一關聯關係測試
* @author 李偉康
*
*/
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class OneToOneTest {
@Autowired
private UsersDao usersDao;
/**
* 添加用戶同時添加角色
*/
@Test
public void test1(){
//創建角色
Roles roles = new Roles();
roles.setRolename("管理員");
//創建用戶
Users users = new Users();
users.setUserage(30);
users.setUsername("趙小剛");
//建立關係
users.setRoles(roles);
roles.setUsers(users);
//保存數據
this.usersDao.save(users);
}
/**
* 根據用戶 ID 查詢用戶,同時查詢用戶角色
*/
@Test
public void test2(){
Users users = this.usersDao.findOne(13);
System.out.println("用戶信息:"+users);
Roles roles = users.getRoles();
System.out.println(roles);
}
}
2:一對多的關聯關係
需求:從角色到用戶的一對多的關聯關係
角色:一方
用戶:多方
2.1:創建Users
@Entity
@Table(name="t_users")
public class Users implements Serializable{
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)//strategy=GenerationType.IDENTITY 自增長
@Column(name="userid")
private Integer userid;
@Column(name="username")
private String username;
@Column(name="userage")
private Integer userage;
@ManyToOne()
@JoinColumn(name="roles_id")
private Roles roles;
public Integer getUserid() {
return userid;
}
public void setUserid(Integer userid) {
this.userid = userid;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public Integer getUserage() {
return userage;
}
public void setUserage(Integer userage) {
this.userage = userage;
}
@Override
public String toString() {
return "Users [userid=" + userid + ", username=" + username + ",userage=" + userage + "]";
}
}
2.2:創建 Roles實體
@Entity
@Table(name="t_roles")
public class Roles {
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="roleid")
private Integer roleid;
@Column(name="rolename")
private String rolename;
@OneToMany(mappedBy="roles")
private Set<Users> users = new HashSet<>();
public Integer getRoleid() {
return roleid;
}
public void setRoleid(Integer roleid) {
this.roleid = roleid;
}
public String getRolename() {
return rolename;
}
public void setRolename(String rolename) {
this.rolename = rolename;
}
@Override
public String toString() {
return "Roles [roleid=" + roleid + ", rolename=" + rolename + "]";
}
}
2.3:一對多的關聯關係操作
/**
* 一對多的關聯關係測試
* @author 李偉康
*
*/
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class OneToManyTest {
@Autowired
private UsersDao usersDao;
/**
* 添加用戶同時添加角色
*/
@Test
public void test1(){
//創建角色
Roles roles = new Roles();
roles.setRolename("管理員");
//創建用戶
Users users =new Users();
users.setUserage(30);
users.setUsername("小王");
//建立關係
roles.getUsers().add(users);
users.setRoles(roles);
//保存數據
this.usersDao.save(users);
}
/**
* 根據用戶 ID 查詢用戶信息,同時查詢角色
*/
@Test
public void test2(){
Users users = this.usersDao.findOne(14);
System.out.println("用戶姓名:"+users.getUsername());
Roles roles = users.getRoles();
System.out.println(roles);
}
}
3:多對多的關聯關係
需求:一個角色可以擁有多個菜單,一個菜單可以分配多個角色。多對多的關聯關係
角色:多方
菜單:多方
3.1:創建 Roles
@Entity
@Table(name="t_roles")
public class Roles {
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="roleid")
private Integer roleid;
@Column(name="rolename")
private String rolename;
@ManyToMany
//@JoinTable:配置中間表信息
//joinColumns:建立當前表在中間表中的外鍵字段
@JoinTable(name="t_roles_menus",joinColumns=@JoinColumn(name="role_id"),inverseJoinColumns=@JoinColumn(name="menu_id"))
private Set<Menus> menus = new HashSet<>();
public Set<Menus> getMenus() {
return menus;
}
public void setMenus(Set<Menus> menus) {
this.menus = menus;
}
public Integer getRoleid() {
return roleid;
}
public void setRoleid(Integer roleid) {
this.roleid = roleid;
}
public String getRolename() {
return rolename;
}
public void setRolename(String rolename) {
this.rolename = rolename;
}
@Override
public String toString() {
return "Roles [roleid=" + roleid + ", rolename=" + rolename + "]";
}
}
3.2:創建 Menus
@Entity
@Table(name="t_menus")
public class Menus {
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="menusid")
private Integer menusid;
@Column(name="menusname")
private String menusname;
@Column(name="menusurl")
private String menusurl;
@Column(name="fatherid")
private Integer fatherid;
@ManyToMany(mappedBy="menus")
private Set<Roles> roles = new HashSet<>();
public Set<Roles> getRoles() {
return roles;
}
public void setRoles(Set<Roles> roles) {
this.roles = roles;
}
public Integer getMenusid() {
return menusid;
}
public void setMenusid(Integer menusid) {
this.menusid = menusid;
}
public String getMenusname() {
return menusname;
}
public void setMenusname(String menusname) {
this.menusname = menusname;
}
public String getMenusurl() {
return menusurl;
}
public void setMenusurl(String menusurl) {
this.menusurl = menusurl;
}
public Integer getFatherid() {
return fatherid;
}
public void setFatherid(Integer fatherid) {
this.fatherid = fatherid;
}
@Override
public String toString() {
return "Menus [menusid=" + menusid + ", menusname=" + menusname + ", menusurl=" + menusurl + ", fatherid=" + fatherid + "]";
}
}
3.3:多對多關聯關係操作
/**
* 多對多關聯關係測試
* @author 李偉康
*
*/
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class ManyToManyTest {
@Autowired
private RolesDao rolesDao;
/**
* 添加角色同時添加菜單
*/
@Test
public void test1(){
//創建角色對象
Roles roles = new Roles();
roles.setRolename("超級管理員");
//創建菜單對象 XXX 管理平臺 --->用戶管理
Menus menus = new Menus();
menus.setMenusname("XXX 管理平臺");
menus.setFatherid(-1);
menus.setMenusurl(null);
//用戶管理菜單
Menus menus1 = new Menus();
menus1.setMenusname("用戶管理");
menus1.setFatherid(1);
menus1.setMenusurl(null);
//建立關係
roles.getMenus().add(menus);
roles.getMenus().add(menus1);
menus.getRoles().add(roles);
menus1.getRoles().add(roles);
//保存數據
this.rolesDao.save(roles);
}
/**
* 查詢 Roles
*/
@Test
public void test2(){
Roles roles = this.rolesDao.findOne(3);
System.out.println("角色信息:"+roles);
Set<Menus> menus = roles.getMenus();
for (Menus menus2 : menus) {
System.out.println("菜單信息:"+menus2);
}
}
}